Wärtsilä NO X Reducer Environmental Efficiency
Environmental efficiency Stringent legislations concerning NO X. Retroactive legislations are introduced. Regulations in the shape of fees, taxes or incentive programs are brought on from many parties, including individual countries that have introduced fairway dues, NO X tax or NO X fund initiatives.
Revised Marpol Annex VI Regulation 13 NO X (g/kwh) 18 16 14 12 10 8 6 4 2 0 Wärtsilä NOR operation area Primary methods operation area Secondary methods operation area 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Rated engine speed (rpm) Tier I >130 kw New ships 2000 Tier II >130 kw New ships 2011 Tier III >130 kw New ships 2016 in designated Emission Control Areas (ECA)
NO X formation and reduction Nitrogen Oxides (NO x x) are formed during the combustion process from oxygen (O 2 ) and nitrogen (N 2 ) in air. The NO X Reducer SCR catalyst converts NO X molecules back to harmless O 2 and N 2 molecules by means of urea.
NO X reducer description The Nitrogen Oxide Reducer (NOR) is designed by Wärtsilä and is based on selective catalytic ti reduction (SCR) technology. The NO X reducer portfolio covers Wärtsilä s medium-speed engine portfolio for marine applications. The size of the NO X Reducer is optimised in terms of modularity, performance and costs. The typical NO X emission reduction is 90 %. The main component of the NO X reducer installation is the reactor with the catalyst inside. Other modular essential parts of NOR system are a reagent pumping unit, a reagent dosing unit, a control unit and an injection unit.
NO X reduction functional principle (SCR) Nitrogen oxides (NO X ) are reduced into nitrogen (N 2 ) and water vapour (H 2 O) using ammonia or urea at a suitable temperature t on the surface of the catalyst. Operating temperature ~ 300 450 C
Minimum recommended temperature in the SCR inlet vs fuel sulphur content
Catalytic elements Proven catalytic elements for marine applications.
NO x Reducer layout NOR reactor Soot blowing Control system cables Compressed air Urea piping Injector Compact unit (dosing & control) Compressed air Urea tank Pump unit
Wärtsilä NOR system overview Dosing / Control unit Dosing / Dosing / Control Control unit unit
Main components Reactor Wide range of sizes designed for various customers needs. High level of standardization and modularisation. Reactor structure optimized for marine applications. Reactor can be run without reagent injection, only soot blowing remains in operation; no by-pass is required. Soot blowing inlets are located on opposite reactor walls for ensuring efficient cleaning which covers the whole element surface area.
Main components Urea injection and mixing The injection unit feeds the optimum amount of urea solution with air to the mixing duct Mixing duct gives the necessary time for urea to evaporate, decompose and mix with exhaust gas Appropriate p mixing duct arrangement ensures uniform flow around the injector to obtain homogeneous distribution of ammonia into the flow When turned off, the injector is automatically purged by compressed air from urea solution in order not to have urea deposits in it.
Main components Urea pumping unit The pumping unit supplies urea solution to multiple dosing units In large multiple engine installations it is possible to simply increase the number of pumps in order to deliver the desired amount of urea All piping is made of stainless steel Preferably accommodated close to the urea tank
Main components Urea dosing unit Defines the correct dosing rate and adjusts urea flow accordingly with a control valve. Combines the control of urea solution dosage and compressed air with automatic ti injector cleaning features. All piping is made of stainless steel. An independent dosing unit for each NOR reactor. Recommended to be installed close to the urea injector.
Main components Control system The control system is a part of the dosing unit Controls the NOR operation by monitoring engine parameters Integrated interface to the engine automation system Hardware and software commonality with the engine automation system UNIC platform Soot blowing control and safety features are included
Wärtsilä NOR performance High activity over a wide temperature range Efficient SCR process Durable catalyst against ageing and erosion Performance NOx emission levels as per IMO Tier III* Urea consumption Typically y 15-20 l/h / MW Operation Fuels: MGO / MDO / HFO with <1.0 % S content (higher sulphur content possible upon request) NOR delivery means ensuring the compatibility of the NOR system with the engine. *at sufficient high exhaust temperature conditions
Selection of NOR reactor for Wärtsilä engines NOR reactor is selected according to engine power.
NO X reducer system typical consumables Reducing agent Compressed air for reducing agent injection and soot blowing Electricity (~1 kw per NOR unit) Catalytic elements TYPICAL COST DISTRIBUTION
NOR Benefits Owner Benefits Quality and functionality guaranteed by Wärtsilä Control system commonality for NOR and the engine Complete system user manual Catalyst system components and service available by Wartsila worldwide Training courses Shipyard Benefits Fully integrated supply by one supplier Possible integration ti with noise attenuation system Single point responsibility Quick installation due to prefabricated and -tested modules Start up and commissioning Calibration expertise Short delivery time